This project will evaluate the feasibility of argon and CO2 lasers for performing ablative microsurgery of the middle ear and semicircular canals of experimental monkey subjects. In addition to delineating safe and appropriate output parameters (burst duration and power levels) for ablating or perforating hard and soft tissues, auditory and vestibular function will be measured electrophysiologically and behaviorally in order to determine if laser microsurgery is accompanied by harmful sensorineural side effects. After completing all functional measurements from 6 months to 1 year postoperatively, the animals will be sacrificed and temporal bone sections processed for evaluation of inner ear morphology. BIBLIOGRAPHIC REFERENCES: Wilpizeski, Chester R., "Otological Applications of Lasers," chapter preparedd for M. Wolbarsht, ed., Laser Applications in Medicine and Biology, Volume 3, Pergamon Press, to be published summer, 1976.